Quotations

1996 (sense 4): In some instances one can take advantage of differential carbohydrate fermentation capabilities of microorganisms by incorporating one or more carbohydrates in the medium along with a suitable pH indicator. Such media are called differential media (e.g., eosin methylene blue or MacConkey agar) and are commonly used to isolate enteric bacilli. — Medical Microbiology, ed. Samuel Baron, MD.

Communication

Data storage device, any physical material that records or holds recorded information

Art medium, materials and techniques used by artists to produce art works

Transmission medium, in physics and telecommunications, any material substance which can propagate waves or energy

Measurement

Natural Science

In general, a medium is a material that is either itself undergoing a process that is being studied or used (e.g. transmission medium), or enabling another process of interest (e.g. growth medium). Specific examples include the following:

Processing medium, in industrial engineering, a material that plays a role in manufacturing processes

Excitable medium, a nonlinear dynamic system which has the capacity to propagate a wave

Growth medium (or culture medium), in biotechnology, an object in which microorganisms or cells experience growth

Interplanetary medium, in astronomy, material which fills the solar system

Interstellar medium, in astronomy, the matter and energy content that exists between the stars within a galaxy

Paranormal and New Age

Mediumship (see article on channel), a practice in which a person acts as an intermediary between the physical world and what is believed to be a spiritual world.